The present invention relates to leaf retaining means, for use for example in a loose-leaf folder.
One well-known construction for this kind of product comprises a plurality of openable rings secured to the spine or rear flap of a folder. The rings may be snapped open and leaves of paper having appropriate holes punched therein can be attached to the rings which can then be snapped shut to retain those leaves in the folder.
A problem encountered with such a construction is the cost of manufacture of the openable and closable rings. The mechanisms concerned occupy a relatively large volume and the folders cannot be packed flat. The mechanisms are made of a different material from the folders thus creating a recycling problem. Furthermore, the ring mechanism requires riveting, either through itself or through a holding plate.
In another previously proposed construction, a multiplicity of discs are provided, each with a flange all the way round its periphery. Leaves which are to be bound together and which may comprise a multiplicity of sheets of paper with hard sheets acting as covers and between which the sheets of paper are sandwiched, have a multiplicity of T-shaped apertures cut through the leaves along the intended spine of the folder. Each T-shaped aperture has the upright of the xe2x80x98Txe2x80x99 perpendicular to the intended spine and opens at that edge of each sheet. This enables one such disc to be inserted into each such aperture so that its flange engages the part of the aperture in each sheet corresponding to the horizontal part of the xe2x80x98Txe2x80x99. Each of the discs engages all the sheets in this way, so that the discs are spaced apart along the spine.
The problem with this construction is that the leaves are still free to slide relative to one another such that the binding becomes strained and even fails.
The present invention seeks to provide a remedy.
Accordingly, a first aspect of the present invention is directed to leaf retaining means for loosely retaining a multiplicity of leaves of material, such as sheets of paper, the leaf retaining means comprising a base portion, which is provided with at least one formation to enable it to be secured directly or indirectly to a folder cover, and loop means, in which the loop means, in section at a given position around the loop means, has at least two points on its surface which two points are closest to an imaginary plane which does not pass through that position and which is perpendicular to the loop means and the base portion and which two points are spaced apart, the loop means being such as to enable a leaf of material, such as a sheet of paper, with a generally T-shaped aperture in it that is open at an edge of the leaf, to be releasably held by the loop means by pushing the aperture onto the loop means.
Whilst the loop means could conceivably comprise two adjacent parallel loops of wire, it is preferable that the loop means comprises a flange around a tongue of the leaf retaining means that extends from the base portion thereof.
The said imaginary plane may be the median bisector of the loop. The said two points may be spaced apart laterally of the general plane in which the loop lies.
Preferably, the flange extends on both sides of the tongue.
Preferably, the said formations comprise at least one groove adapted to be engaged by a corresponding internal edge of a folder.
In one advantageous form of the invention, the loop means are narrower at a top of the loop means to facilitate the addition or removal of leaves to the folder.
The first aspect of the present invention extends to a combination of at least two such retaining means and a folder being provided with at least two apertures at or adjacent to a spine of the folder at the respective ends thereof, the shape of each hole in the folder corresponding to that of the base portion of each such retaining means, the latter having been slid into the apertures in the folders.
This aspect of the present invention also extends to a folder having such retaining means and leaves of material, such as sheets of paper, formed with generally T-shaped apertures at the two ends of one side thereof for engaging the said retaining means, the T-shaped apertures opening at one of the edges of the leaf.
Each leaf may comprise a folded sheet with the T-shaped apertures being formed at the fold. As a result, if there are only two retaining means at a top and bottom of this sheet, the latter may be opened whilst still being retained in the retaining means and in the opened state there is substantially no obscurity of the central regions of the opened leaf.
Preferably, the folder has two parallel slots extending away from each aperture formed therein, so that the material of the folder between the slots yields to facilitate insertion of the base portion of the retaining means into the aperture of the folder and then the part of the material between the slots may be snapped against one end of the base portion of the retaining means to firmly secure the latter in the folder. At least one groove in the base portion of the retaining means can be provided to receive an edge of this folder material between the slots.
The folder may be made of a metal or metal alloy. In that case, at least some of the internal edges which define the apertures may be serrated to improve the securing of the retaining means in the folder.
According to a second aspect of the present invention, there is provided retaining means for retaining a multiplicity of leaves of material, such as sheets of paper, in a folder comprising a retainer extending upwardly from a base portion of the retaining means, the base portion being provided with a groove to engage inner edges of a folder.
According to a third aspect of the present invention, there is provided a folder cover, at least one leaf retainer extending from the inside of a cover, and at least one removable leaf of material, such as a sheet of paper, having a T-shaped aperture cut at an edge thereof so that what constitutes the upright of the xe2x80x98Txe2x80x99 is open at an edge of the leaf.
The present invention extends to a stamp device for stamping two such T-shaped apertures at the ends of an edge of a leaf of material, such as a sheet of paper.
Examples of retaining means made in accordance with the present invention will now be described with reference to the accompanying drawings, in which: